In making connections to a terminal box such as used to service a shop, residence or mobile home, a plurality of electric lines or cables (sometimes carrying reduced voltage from that of the incoming service line) are individually coupled to a connector box's bank of circuit breakers. The cables are then bent in order to take them off in another direction through an aperture in the top or bottom of the box. If the bending is not done in a fairly broad arc, it may crack or break the insulation of the cable, sometimes immediately but often later upon aging. Even though the bared wire does not directly touch a conductor at the time of rupture, its presence may become more dangerous later when combustable gas may leak or accumulate into the box, since a spark to the immediate environment (sometimes from lightening) may short the current of the exposed line and flare out to consume a transformer plus the rest of the installation.
A remedy to this problem is sought by promulgation of more stringent electrical code requirements which prescribe the minimum radius for such cable bends. The initial result of new regulations may be to compell larger size boxes in future construction. However this raises a more difficult problem in attempting to make alterations of in-place installations where it becomes impractical to try to enlarge the box size to meet a 5 to 7 times radius for a safe bend; the result may have to be a completely new assembly.